Just seven years after his D.C. metro debut, Joshua Bell took to the Union Station stop for a similar social experiment--however, this time he would be far from ignored.

Bell's publicist, Jane Covner, said that the performance was supposed to feel impromptu, and that's exactly what he accomplished. Crammed into a marble hall, patrons, passersby and people of all shapes and sizes stood to watch the world-famous violinist take the makeshift stage.

With the children in mind, Bell aimed to promote music to children with the performance. And, in fact, the entire front row of the assembly was littered with children, who were more excited than their parents.

Though more accustomed to a silent stage for to perform Bach, the metro didn't undercut the performance. Of all the places that have brought Bell to a crowd, for some reason this gleams as one of his most intimate.